A week after yielding the stage to the backups, the Patriots franchise quarterback will make his preseason debut tonight against the Eagles at Gillette Stadium, according to a source. Ryan Mallett and rookie Jimmy Garoppolo will man the clipboards before commanding the huddle once Brady exits, though it’s unclear how long the 37-year-old might play.

Regardless, each signal caller will harness his own unique storyline, which spices up tonight’s exhibition affair. Brady almost certainly will continue his summer sizzle while Mallett and Garoppolo grapple for backup duties that could ultimately determine the remaining length of Mallett’s stay with the Patriots.

Brady, for starters, has been an executioner of NFC East defenses during the past couple of weeks. He completed 100-of-138 passes (72.5 percent) in team drills during four padded practices against the Redskins and Eagles, including 40-of-58 (69 percent) this week.

But the enticement of live game reps never fails to get Brady’s blood flowing. Last week, the quarterbacks found out late on the night before the game Brady would give way to Mallett. This week, the three QBs were apprised of their workload much earlier.

“I’ll be ready to play for as long as (Bill Belichick) wants me to,” Brady said. “That’s very valuable playing experience for me, too. It doesn’t matter how many years you’ve been doing it. You’ve got to get out there and play under game situations and get your body going at the level that it needs to be at.”

Mallett has been fighting through a left knee injury that he suffered last week against the Redskins, and it forced him out of action Sunday and Monday before he returned Tuesday on a limited basis. While all three quarterbacks were on the field for the two padded workouts against the Eagles, Mallett was second in the rotation, so that might be a precursor to the way they’re used tonight.

Mallett downplayed the ailment yesterday and said he was ready to go. Though there is no structural damage, which has been made obvious by his attendance, it’s known Mallett is fighting through pain to remain on the field. He completed 8-of-12 passes in team drills this week and is looking to improve upon an up-and-down showing in the opener.

“Anytime you get a rep, when you’re not the starter, you’ve got to take advantage of it because you don’t get all the reps,” Mallett said. “So that’s why I treat every practice like that, whether it’s joint, or we’re practicing each other.”

Garoppolo, meanwhile, jumped out of the phone booth this week. After being unable to string any consistency together through the first 11 practices, Garoppolo was an unexpected star by completing 9-of-13 passes for 157 yards and the team’s lone touchdown, which spurred a hot streak this week. He completed 13-of-17 passes in team drills against the Eagles.

Because the Patriots have a four-year commitment to Garoppolo, compared to one remaining season with Mallett, it’s literally a matter of time until the team determines which one is more worthy of being Brady’s backup. If Garoppolo’s surge continues over the next two weeks, that call could come sooner than expected, especially relative to their observations from 10 days ago.

More immediately, proficient play from each backup will help the entire operation.

“Whatever we do, whoever is out there has to go out there and execute because our team really counts on that,” Brady said. “If the quarterback doesn’t play well, then it will pretty much (stink) for everybody else, so we’ve got to go out there and do the best we can.”

Since Brian Hoyer arrived in 2009, Belichick has proven his affinity for keeping just two quarterbacks on the 53-man roster. If Garoppolo continues his trajectory, Belichick could be more active in his attempt to shop Mallett as opposed to simply listening to the several inquiries that have hit his Foxboro office over the past year and a half.

Of course, the Patriots are reliant upon some productive performances to make that happen, particularly as they open the press box tonight for NFL scouts to pay a visit. Some more efficiency from Mallett wouldn’t hurt tonight, either.

When it comes to Brady, Mallett and Garoppolo, there’s still plenty on the line for tonight’s exhibition game.

“We always look forward to the games,” Brady said. “You play the game. You don’t work the game, so that’s what we’re trying to do. We’re trying to go out and play and have a lot of fun. We’ve got a day of prep (yesterday), and then we’ll go out and let it rip (tonight).”